Merge or join surfaces generated in sverchek . Curves made by Bezier
for now it is one solution
http://nikitron.cc.ua/sverch/html/nodes/surface/blend_surface.html
but we need sewing node, that will do it between zero-space between surfaces.
https://gist.github.com/23349d01c4df05934ef8833d92d27629
try this gist as example